Comment 19 for bug 738789

Just a note that I still get this occasionally in Ubuntu 16.04 and 16.10, usually after moving to a new series of the nvidia driver, and my case the problem is that nvidia overwrites the /usr/lib/xorg/modules/extensions/libglx.so and /usr/lib/x86_64-linux-gnu/libGL.so files (eg "ldd /usr/lib/x86_64-linux-gnu/libGL.so|grep -i nvidia" shows nvidia in the file).

A workaround when this happens is to install nvidia-prime and run "sudo prime-select intel" to reset to using the intel libraries.